which one is more insulting youre ugly because youre fat or youre ugly because you look like a boar i think the latter is less insulting because even though a person who does actually resemble a boar would be extremely ugly its unlikely that it was meant literally same goes for your case when you call someone a piece of shit youre almost certainly aware of the fact that they arent a literal piece of shit and so this is intended as a general insult or as a standard metaphor for selfish behavior etc when you call someone a nigger as an insult its not as clear that you dont actually view them as literally inferior beings and so thats more insulting